Add MsalRemainingTokenLifetime histogram for token expiry by neha-bhargava · Pull Request #5920 · AzureAD/microsoft-authentication-library-for-dotnet

neha-bhargava · 2026-04-10T22:44:11Z

Add new OTel histogram (MsalRemainingTokenLifetime.1A) that records the remaining lifetime of tokens in seconds at the time of acquisition.

Tags (6/8): MsalVersionPlatform (combined), ApiId, TokenSource, CacheLevel, CacheRefreshReason, TokenType.

Also adds TelemetryTokenTypeConstants.ToDisplayString() helper for int-to- string token type mapping used by the new histogram.

Resolves: #5889
PBI: 3554274

Fixes #

Changes proposed in this request

Testing

Performance impact

Documentation

All relevant documentation is updated.

…vability Add new OTel histogram (MsalRemainingTokenLifetime.1A) that records the remaining lifetime of tokens in minutes at the time of acquisition. Tags (6/8): MsalVersionPlatform (combined), ApiId, TokenSource, CacheLevel, CacheRefreshReason, TokenType (human-readable string). Also adds TelemetryTokenTypeConstants.ToDisplayString() helper for int-to- string token type mapping used by the new histogram. Resolves: #5889 PBI: 3554274 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

Adds a new OpenTelemetry histogram (MsalRemainingTokenLifetime.1A) to capture token time-to-expiry at acquisition time, and wires it into the successful token acquisition telemetry path. This supports the requested MSAL telemetry enhancement for remaining token lifetime.

Changes:

Added MsalRemainingTokenLifetime.1A histogram emission (with tags) in OtelInstrumentation and invoked it from the success telemetry path.
Added TelemetryTokenTypeConstants.ToDisplayString(int) to emit a human-readable token type for the new metric.
Updated OTel unit tests to account for the additional exported metric and validate tags for the new histogram.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tests/Microsoft.Identity.Test.Unit/TelemetryTests/OTelInstrumentationTests.cs	Updates expected metric counts and adds tag validation for the new remaining-lifetime histogram.
src/client/Microsoft.Identity.Client/TelemetryCore/TelemetryConstants.cs	Adds `MsalVersionPlatform` tag key constant used by the new metric.
src/client/Microsoft.Identity.Client/TelemetryCore/OpenTelemetry/IOtelInstrumentation.cs	Extends the instrumentation interface with `LogRemainingTokenLifetime(...)`.
src/client/Microsoft.Identity.Client/TelemetryCore/OpenTelemetry/NullOtelInstrumentation.cs	Implements the new interface method as a no-op for null instrumentation.
src/client/Microsoft.Identity.Client/Platforms/Features/OpenTelemetry/OtelInstrumentation.cs	Defines and records the new `MsalRemainingTokenLifetime.1A` histogram.
src/client/Microsoft.Identity.Client/Internal/TelemetryTokenTypeConstants.cs	Adds an int→string token type mapping helper for telemetry display.
src/client/Microsoft.Identity.Client/Internal/Requests/RequestBase.cs	Calls `LogRemainingTokenLifetime(...)` during successful request telemetry logging.

Robbie-Microsoft · 2026-04-20T21:28:39Z

+                        expectedTags.Add(TelemetryConstants.ApiId);
+                        expectedTags.Add(TelemetryConstants.TokenSource);
+                        expectedTags.Add(TelemetryConstants.CacheLevel);
+                        expectedTags.Add(TelemetryConstants.CacheRefreshReason);


Test validates tags but never asserts the recorded histogram value

Robbie-Microsoft

PR description says tags are "6/8" but only 6 are emitted. The description mentions 8 planned tags - it's unclear which 2 are missing and whether that's intentional or an oversight worth clarifying.

- Merge LogRemainingTokenLifetime into LogSuccessMetrics (ssmelov comment) - Remove duplicate GetCacheLevel call, compute once and reuse (Robbie +1) - Use int for TokenType tag instead of string for consistency with other metrics - Remove ToDisplayString helper (no longer needed with int TokenType) - Add histogram value assertions in test (count > 0, sum >= 0) - XML doc correctly says seconds (align PR description accordingly) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

The new MsalRemainingTokenLifetime histogram adds one more metric to the export, bringing the total from 5 to 6. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Copilot · 2026-04-29T22:54:00Z

+        /// <summary>
+        /// Histogram to record the remaining lifetime of acquired tokens in seconds.
+        /// </summary>
+        internal static readonly Lazy<Histogram<long>> s_remainingTokenLifetime = new(() => Meter.CreateHistogram<long>(
+            RemainingTokenLifetimeHistogramName,
+            unit: "s",
+            description: "Remaining lifetime of acquired tokens at the time of acquisition."));


PR description says MsalRemainingTokenLifetime.1A should record remaining token lifetime in minutes, but the instrument is defined/recorded in seconds (unit "s" and TotalSeconds). Either update the implementation/unit to minutes, or update the PR description and any downstream expectations to explicitly be seconds.

Copilot · 2026-04-29T22:54:00Z

+                s_remainingTokenLifetime.Value.Record(remainingSeconds,
+                    new(TelemetryConstants.MsalVersionPlatform, $"{MsalIdHelper.GetMsalVersion()},{platform}"),
+                    new(TelemetryConstants.ApiId, apiId),
+                    new(TelemetryConstants.TokenSource, authResultMetadata.TokenSource),
+                    new(TelemetryConstants.CacheLevel, cacheLevel),
+                    new(TelemetryConstants.CacheRefreshReason, authResultMetadata.CacheRefreshReason),
+                    new(TelemetryConstants.TokenType, authResultMetadata.TelemetryTokenType));


PR description calls out TokenType tag as a human-readable string and mentions adding a TelemetryTokenTypeConstants.ToDisplayString() helper, but this metric records authResultMetadata.TelemetryTokenType (an int). If TokenType is intended to be a display string for this histogram, convert the int to the display string (e.g., via the helper) before tagging; otherwise, update the PR description to match the emitted tag value type.

neha-bhargava requested a review from a team as a code owner April 10, 2026 22:44

Copilot AI review requested due to automatic review settings April 10, 2026 22:44

Copilot started reviewing on behalf of neha-bhargava April 10, 2026 22:45 View session

Copilot AI reviewed Apr 10, 2026

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ssmelov reviewed Apr 20, 2026

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Comment thread src/client/Microsoft.Identity.Client/Platforms/Features/OpenTelemetry/OtelInstrumentation.cs Outdated

Robbie-Microsoft reviewed Apr 20, 2026

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Comment thread src/client/Microsoft.Identity.Client/Internal/TelemetryTokenTypeConstants.cs Outdated

Robbie-Microsoft reviewed Apr 20, 2026

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Comment thread src/client/Microsoft.Identity.Client/Platforms/Features/OpenTelemetry/OtelInstrumentation.cs

neha-bhargava and others added 2 commits April 29, 2026 14:50

Fix integration test: update expected metric count to 6

3742b3b

The new MsalRemainingTokenLifetime histogram adds one more metric to the export, bringing the total from 5 to 6. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot AI review requested due to automatic review settings April 29, 2026 22:50

Copilot started reviewing on behalf of neha-bhargava April 29, 2026 22:50 View session

Copilot AI reviewed Apr 29, 2026

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gladjohn mentioned this pull request May 1, 2026

[Engineering task] Copilot PR Review: excessive noise from review_on_push and false positives #5967

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Add MsalRemainingTokenLifetime histogram for token expiry #5920

Add MsalRemainingTokenLifetime histogram for token expiry #5920
neha-bhargava wants to merge 3 commits intomainfrom
nebharg/otelRemainingTokenLife

neha-bhargava commented Apr 10, 2026 •

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neha-bhargava commented Apr 10, 2026 •

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